Air hammer and combined support and muffler therefor

ABSTRACT

A support by which a reciprocating air hammer of the type having an elongated body or barrel is pivotally supported on the bucket supporting boom arm of a conventional power shovel, is modified to enclose the hammer body and to muffle the air percussively discharged from the hammer body.

United States Patent Gunning 1 1 Sept. 11, 1973 AIR HAMMER AND COMBINEDSUPPORT 3,667,571 5 1971 Fattelay 181/36 A AND MUFFLER THEREFOR3,599,756 8/1971 Pickle 2,128,742 8/l938 Fuehrer 173/134 X [75]Inventor: Samuel D. Gunning, Cleveland, Ohio [73] Ass1gnee: Kent AllTool Co., Kent, Oh10 Primary Examiner Emest R Purser [22] Filed: Nov.24, 1971 Attorney-John Harrow Leonard [21] Appl. No.: 201,933

57 ABSTRACT [52] US. Cl 173/44, 173/46, 173/DlG. 2,

181/36 A A support by which a reciprocatingair hammer of the [51] it.Cl. F01" 7/00, 325d l7/l2 yp having an eongated y or barrel is pivotally[58] Field of Search 173/43, 44, l34139, supported on the bucketSupporting boom arm of a 2 conventiona ower s ove is m i 1e to enc ose te 173/46 DIG 2 l8l/36A 1p h 1 odf d 1 h hammer body and to muffle theair percussively dis- [56] References C'ted charged from the hammerbody.

UNITED STATES PATENTS 12/1965 Price 173 134 X 8 Claims, 7 DrawingFigures PATENTED 11 75 sum 2 or 3 INVENTOR.

SAMUEL D. GU NNING N ATTORNEY.

' SHEEI a era MEQK INVENTOR.

SAMUEL D. GUNN l NG ATTORNEY.

AIR HAMMER AND COMBINED SUPPORT AND MUFFLER THEREFOR BACKGROUND OFINVENTION 1. Field of Invention Tool driving or impacting, pneumaticallyoperating, axially reciprocating device with combined support andexhaust muffler.

2. Description of Prior Art Air hammers of the general type hereindescribed are well known in the art, the one shown for illustration inthe present application being that disclosed in my copendingapplication, Ser. No. 10,826, filed Feb. 12, 1970, entitled Air Hammerand issued as United States Letters Pat. No. 3,625,295 on Dec. 7, 1971.As therein more fully disclosed, the hammer comprises an elongated bodyor barrel which is disposed between and connected at its rear end infixed relation to a pair of laterally spaced supporting plates. Theplates, in turn, are pivotally connected to the bucket supporting arm ofa conventional power shovel so that the hammer can be moved bodily withthe arm and rocked about a horizontal axis to different operatingpositions relative to the arm. The same plates are pivotally connectedto the piston and cylinder assemblage which is provided for operatingthe bucket. Thus the air ham'mer can be directed at different angles tothe arm, selectively, and held at the selected angle during operation.This hammer, and other hammers of this general type, exhaust the airpercussively directly to the atmosphere with the result that the exhaustcreates a very loud and ir ritating noise. Mufflers of some types havebeen used to reduce the noise thus created, but have not proven assatisfactory as desired.

SUMMARY OF INVENTION The present invention is directed to the mufflingof the percussively discharged air so as to reduce noise greatly. Morespecifically it is directed to the use of the therein, part thereofbeing broken away for elearncss in illustration;

FIG. 3 is a side elevation of the structure illustrate in FIG. 2, partthereof being shown in section;

FIG. 4 is a fragmentary front end elevation of the structure illustratedin FIG. 1;

FIG. 5 is a fragmentary cross sectional view of the structureillustrated in FIGS. I and 2, and is taken on the line 55 thereof;

FIG. 6 is a fragmentary cross sectional view of the structureillustrated in FIGS. 1 and 2 and is taken on the line 66 thereof; and

FIG. 7 is a fragmentary rear end elevation of the structure illustratedin FIGS. 1 and 2.

Referring first'to FIG. 1, the present invention is shown as supportedon the bucket supporting arm A of a boom B of a conventional powershovel for rocking to different selected operating positions by a pistonand side supportingplates for the hammer'as a structural part of themuffler. This is accomplished by extending the supporting plates to alocation near the front of the hammer and securing them thereto near theforward end as well as the rear end, thus greatly increasing therigidity of the support. The, space between the plates is closed at thetop and bottom of the plates to provide an enclosing muffling housinginto which the exhaust air is discharged and through which it isconstrained to flow in a tortuous baffled path so as to discharge nearthe rear of the hammer with a greatly reduced percussiveness. v

This is accomplished without adding appreciably to the overalldimensions of the supported hammer, the hammer being, in effect, mountedwithin the muffler.

Various other objects and advantages of the invention will becomeapparent from the following description in which reference is made tothe drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of thecombined support and muffler of the present invention, with the. hammersupported thereby and with the muffler, in turn, supported on the bucketsupporting arm of a conventional power shovel;

.FIG. 2 is an enlarged top plan view of the combined support and mufflerwith the air hammer mounted cylinder assemblage C of the power shovelwhich conventionally is connected to the bucket.

The hammer has a body 1 comprising a barrel 2 which is closed at thefront end by a suitable header or block 3 with a tool supportingextension 30, and a cylindrical cover 3b. At the rear end the barrel 2is closed by a header or block 4. The barrel 2 is secured fixedlybetween the blocks 3 and 4 by tie rods 5. Air under pressure foroperating the hammer is admitted through a suitable hose through therear block 4. Near its forward end the body 1 has an exhaust port 7which, in the structure shown, is in the block 3'and opens through thecover 3b and exhausts directly into the atmosphere. A tool 8 is carriedby the extension 3a of the body 1 and is operated by the air drivenmechanism within the body in the conventional fashion. The interioroperating parts of the hammer are fully disclosed in my identifiedpatent and, not being a part of the present invention, are notspecifically illustrated herein.

The body 1 is supported between two rigid upright side plates 10. Theplates 10 have means for pivotal connection to the arm A for rockingrelative thereto about a horizontal pivotal axis and have means forconnection to the piston rod of the piston and cylinder assemblage C sothat the plates can be rocked as a unit about the horizontal pivotalaxis to different positions. The means for connecting the plates to thearm A comprise ,a pair of aligned coaxial bores 11 in the plates andwhich are adapted to receive a pivot 12 usually provided for pivotallymounting the bucket.1The means for connecting the plates to theassemblage are aligned coaxial bores 13 adapted to be pivotallyconnectedby a pivot 14 to a multiplying linkage D which is driven by thepiston and cylinder assemblage C normally for rocking the bucket aboutthe axis of the pivot 12.

The plates 10 are connected in firm face to face juxtaposition withopposite side faces of the mounting block 4 of the air hammer bysuitable tie bolts 16 so as to hold the block, and thereby the hammerbody 1 in its entirety, in fixed position relative to the plates 10. Thestructure thus far described is that of my above identified patent. Inaccordance with the present invention, the plates 10 are extendedforwardly from the block 4 beyond the front block 3 and extension 3a,almost to the forward end of the air hammer body 1, as distinguishedfrom my prior hammer in which the side plates terminated forwardly. atthe forward face of the block 4. At the forward ends of the plates 10,rigid clamping blocks 17 are disposed between the plates 10. Theseblocks have cutout portions which provide wall portions, as indicated at18, which engage the exterior of the body extension 3a for securing thefront end of the body in firm clamped position relative to the plates10. 'Suitable clamping bolts 19 draw the plates 10 firmly against theblocks 17 and the blocks 17 into firm clamping relation with theextension 3a. Thus the hammer is firmly secured in fixed positionrelative to the plates 10 at both of its ends to form therewith a rigidunitary structure. Due to the depth of the plates 10 and their extentendwise of the body 1, the structure is highly resistant to bendingmoments both about and transversely of the axis of the pivot 12. Theplates 10 extend from a location above the body 1 to a locationtherebelow, and the space between the plates is closed at the top and atthe bottom, respectively, by rigid covers 20.

Each cover 20 bridges across the entire space between the plates 10 andis secured in fixed position relative to the plates 10 by means of bolts21 threadably engaged with suitable lugs 22 secured to the inner facesof the plates 10. Each cover 20 has an integral depending flange portion23 at its forward end. The flange portion 23 extends toward the axis ofthe body 1 and terminates substantially at a horizontal diametral planethrough the axis so as to surround the body with slight radial clearanceand substantially close the front end of the resultant housing providedby the side plates land the covers 20. i

In order to provide an effective seal to prevent the escape of theexhaust air from the forward end of the resultant housing, a suitablesoft or resilient foamed rubber or elastomeric gasket 24 is provided onthe inner face of each depending flange portion 23. The gasket 24 issuch as to bridge the clearance space between the inner peripheral edgesof the flange portions 23 and the outer peripheral surface of theextension 3a of the body 1. As a result of this seaL'the air exhaustedpercussively from the port 7 is constrained from passing out of thefront of the housing. The vibrations caused by the percussive exhaustare damped and not directly transmitted from the body 1 to the dependingflange 23.

At its rear end each cover 20 has a flange portion 26, offset outwardlyfrom its normal plane, which is positioned in outwardly spaced relationfrom the corresponding top or bottom edge face of the block 4. Suitablespacers 27 are disposed between the flange 26 and the adjacent edge faceof the block 4 for assuring the spacing of the flange 26 from the faceof the block 4 at all times.

As is illustrated in the drawing, the covers 20 and the side plates arein spaced relation to the peripheral wall of the body 1 from a positionforwardly of the exhaust port 7 to a position near the forward face ofthe block. The flanges 26 are also spaced from the block 4 and definewith the top and bottom edge faces of the block 4 air discharge openings29. The openings 29 are conneted with the space defined by the covers 20and side walls 10 on the one hand and the peripheral exterior wall ofthe body 1 on the other, so that the exhaust air percussively issuingfrom the port 7.is discharged through the housing passage and theopenings 29 into the atmosphere at the rear of the body.

It is desirable for muffling purposes that the exhaust air passagewithin the housing formed by the plates 10 and the covers 20 be atortuous path having restricted portions along its length so as todissipate the percussive blast of the exhaust and deliver a more uniformflow of air to the outside atmosphere. For this purpose, baffles 30 areprovided within the exhaust air passage in the housing at a locationbetween the exhaust port 7 and the exhaust openings 29. One such baffle30 is shown for purposes of illustration, and comprises a metal plate 31having a central passage 32 which accommodates the body 1 of the hammerwith slight radial clearance. Secured in overlying relation to one sideof the plate 31 is a resilient gasket or sealing pad 33, which may befoamed rubber. The pad 33 has a central opening 34 which is sufficientto bridge the clearance space between the edge wall defining the passage32' and the exterior peripheral wall of the body 1, thus providing aneffective seal therebetween and preventing vibrations of the body 1 frombeing transmitted to the plate 31. The plate 31 extends entirely acrossthe space between the two side plates 10, but is ofless height than thedistance between the inner faces of the covers 20 thereby providingrestricted passages 35 past the baffle 30 at its top and bottom. As aresult, the air from the exhaust port 7 is discharged into a largeexhaust passage in which a large volume of air dampensits immediatepercussive shock. The air then flows at a relatively high speed and at amore nearly uniform velocity through the restricted passage 35, whichfurther dampens the percussive effects, and then again expands, thusfurther reducing the percussive and pulsating effect. Finally the air isdischarged at relatively high speed and at a still more nearly uniformflow through the restricted openings 29, being reduced to pulsationswhich cause much less noise than the staccato bark which would be causedwere the air discharged from the port 7 directly into the atmosphere.

For securing the side plates 10 and covers 20 fixedly at positionsrelative to the midportion of the hammer body and for supporting the.baffle 30, plates 37 are provided. These plates 37 are juxtaposedagainst the inner faces of the side plates 10 at their outer faces andhave concavities 38 at their inner faces, the walls of which firmlyembrace the outer peripheral wall of the barrel 2. They may be welded tothe barrel, if desired. In the form shown, the plates 37 are held infirm clamping engagement with the barrel 2 and with the side plates 10by means of suitable tie bolts 39. 1

The baffle 30 is disposed so that the lateral edges of the pad 33 isdisposed against the forwardly facing edges of the baffle supportingplates 37. Accordingly, the pad 33 is held firmly in place bycompression at its lateral edges between the metal plate 31 andforwardly facing edges of the plates 37.

For holding the plate 31 in proper vertical position, suitable cams 40are provided on the covers and arranged with the cam surfaces slopinginwardly of the body 1 in a direction toward the front of the body sothat, as the covers are drawn firmly in place by the bolts 21, the camsengage the plate 31 of the baffle 30 and center it and urge it firmlyagainst its resilient foam rubber padv 33.

It is apparent that with this arrangement the air percussivelydischarged from the port 7 is muffled by passing along a tortuous paththrough an exhaust passage which has first a portion with a very largecross sectional area relative to the area of the port 7, then, whererestricted by the baffle 30 part way of the length of the passage, andthen final restricting passages 29 as the air is discharged into theatmosphere. The repeated discharge of the exhaust air into a largespace, its restricted flow from that space followed by anotherrestriction of flow reduces the sharp percussive blasts of the air to amore uniform pulsating high speed flow so that the noise level isreduced to about half of that usually occurring when the air from theexhaust port 7 is discharged directly into the atmosphere. This level isbelow that at which the noise is too loud for conversation and is veryirritating and painful to the ears. Having thus described my invention,I claim: 1. An air hammer including a rigid body having an exhaust portand adapted to support a tool at one end; a rigid elongated hollowmuffler housing enclosing said body from a location near said one end ofthe body to a location near the other end of the body and secured to thebody in fixed position relative thereto, and having a discharge openingspaced from said port; the peripheral wall of said housing being spacedfrom the body so as to provide an exhaust passage therebetween andaffording communication between the opening and the port; meansconstraining the air discharged from the port to discharge through theopening; first connecting means on and rigid with the housing at saidother endof the body and adapted for pivotally connecting the housing toa power driven movable support for rocking of the housing in a fixedpath about a predetermined axis extending transversely of the. body andfor transmitting heavy working load forces to the housing bythe powerdriven movable support; second connecting means on the housing at saidother end of the body and having a pivotal axis offset transversely fromsaid predetermined axis, and adapted for pivotal connection to areciprocable power device on the power driven support for rocking thehousing about said pivotal axis by heavy working load forces applicableby the device independently of the movement of the movable support, whenthe housing isconnected to said movable support; and

said housing. being sufficiently rigid and strong to blast of the airdischarged from said port before the air reaches said discharge opening.I

3. The structure according to claim 2 wherein said baffle means comprisea sheet of metal extending transversely of, and surrounding, the body ata predetermined location, and blocking the major portion of the crosssection of said passage at said location, and having an outer peripheraledge portion spaced from the wall of the housing and providing a passagebetween said edge portion and said wall.

4. The structure according to claim 1 wherein the housing has side wallswhich are rigid supporting plates, respectively,-and each of which isconnected at its opposite ends to the opposite ends of the body forsupporting the body by, and in fixed relation to, the plates;

a movable support is pivotally connected to the plates by said firstconnecting means;

power driven means are carried by the movable support and are pivotallyconnected to the plates by said second connecting means; and

said plates are disposed at opposite sides of the body,

respectively, and are capable in and of themselves of transmitting saidheavy working load forces directly from said other end of the body tosaid one end of the body.

5. The structure according to claim 1 wherein the muffler housingincludes two strong rigid working load forces transmitting supportingplates disposed at opposite sides of the body, respectively; each plateis rigidly connected to the body near opposite ends of the body,respectively;

said first connecting means are on, and rigid with said plates; and saidsecond connecting means are on and rigid with said plates.

6. The structure according to claim 1 wherein the end of the bodyopposite from said one end is a block rigidly connected to, and insupporting relation to, the remainder of the body;

the muffler housing includes two rigid, heavy working load forcetransmitting and supporting plates extending alongside opposite sides ofthe body from said block toward said one end of the body;

means fixedly secure the plates to the block; and

additional means secure the plates to the body near the said one end.

7. The structure according to claim 1 wherein a power driven movablesupport is provided;

the muffler housing is rigidly fixedly connected to the body at theopposite ends of the body, respectively, and supports the body;

the first connecting means secures one end of the housing to the movablesupport and supports the housing for movement with the movable support,and for rocking relative to the movable support about the pivotal axisto different working positions relative to the movable support; wherebythe working forces applied by the support to the tool is transmittedthrough the housing from one end of the body to the other end of thebody without subjecting the body between its ends to said forces;

and

power means'are mounted on the movable support and connected to thehousing so as to be operable to manipulate the housing and thereby thehammer, to different positions relative to the power driven movablesupport and against the work with working force.

8. A pneumatic hammer including an elongated rigid body adapted tosupport a tool at one end;

a'pair of rigid supporting plates arranged alongside opposite sides ofthe body;

means securing each plate fixedly to the body at the opposite ends ofthe body, respectively;

a first connecting means on and rigid with the plates at the other endof the body and adapted for pivotally connecting the plates to a movablepower driven support for rocking as a unit, with the body, about apredetermined axis extending transversely of the body, and operative totransmit directly to the plates at said other end of the body any heavyworking load forces imposed by the movable support;

second means on, and rigid with, the plates at said other end of thebody and offset transversely from said predetermined axis and adaptedfor pivotal connection to a reciprocable power device on said supportfor rocking the plates and body as a unit about an axis offset from saidpredetermined axis and operative to transmit heavy working load forcesfrom said reciprocable power device directly to the plates at said otherend of the body; and

said plates, when secured to the body, in and of them-

1. An air hammer including a rigid body having an exhaust port andadapted to support a tool at one end; a rigid elongated hollow mufflerhousing enclosing said body from a location near said one end of thebody to a location near the other end of the body and secured to thebody in fixed position relative thereto, and having a discharge openingspaced from said port; the peripheral wall of said housing being spacedfrom the body so as to provide an exhaust passage therebetween andaffording communication between the opening and the port; meansconstraining the air discharged from the port to discharge through theopening; first connecting means on and rigid with the housing at saidother end of the body and adapted for pivotally connecting the housingto a power driven movable support for rocking of the housing in a fixedpath aboUt a predetermined axis extending transversely of the body andfor transmitting heavy working load forces to the housing by the powerdriven movable support; second connecting means on the housing at saidother end of the body and having a pivotal axis offset transversely fromsaid predetermined axis, and adapted for pivotal connection to areciprocable power device on the power driven support for rocking thehousing about said pivotal axis by heavy working load forces applicableby the device independently of the movement of the movable support, whenthe housing is connected to said movable support; and said housing beingsufficiently rigid and strong to transmit directly from each end of thehousing to the other end of the housing both longitudinal and transverseheavy working load forces applied to the housing at the other end of thebody through said first and second connecting means and to said one endof the housing through the tool end of the body.
 2. The structureaccording to claim 1, wherein baffle means are provided in the housingbetween the exhaust port and discharge opening for reducing thepercussive blast of the air discharged from said port before the airreaches said discharge opening.
 3. The structure according to claim 2wherein said baffle means comprise a sheet of metal extendingtransversely of, and surrounding, the body at a predetermined location,and blocking the major portion of the cross section of said passage atsaid location, and having an outer peripheral edge portion spaced fromthe wall of the housing and providing a passage between said edgeportion and said wall.
 4. The structure according to claim 1 wherein thehousing has side walls which are rigid supporting plates, respectively,and each of which is connected at its opposite ends to the opposite endsof the body for supporting the body by, and in fixed relation to, theplates; a movable support is pivotally connected to the plates by saidfirst connecting means; power driven means are carried by the movablesupport and are pivotally connected to the plates by said secondconnecting means; and said plates are disposed at opposite sides of thebody, respectively, and are capable in and of themselves of transmittingsaid heavy working load forces directly from said other end of the bodyto said one end of the body.
 5. The structure according to claim 1wherein the muffler housing includes two strong rigid working loadforces transmitting supporting plates disposed at opposite sides of thebody, respectively; each plate is rigidly connected to the body nearopposite ends of the body, respectively; said first connecting means areon, and rigid with said plates; and said second connecting means are onand rigid with said plates.
 6. The structure according to claim 1wherein the end of the body opposite from said one end is a blockrigidly connected to, and in supporting relation to, the remainder ofthe body; the muffler housing includes two rigid, heavy working loadforce transmitting and supporting plates extending alongside oppositesides of the body from said block toward said one end of the body; meansfixedly secure the plates to the block; and additional means secure theplates to the body near the said one end.
 7. The structure according toclaim 1 wherein a power driven movable support is provided; the mufflerhousing is rigidly fixedly connected to the body at the opposite ends ofthe body, respectively, and supports the body; the first connectingmeans secures one end of the housing to the movable support and supportsthe housing for movement with the movable support, and for rockingrelative to the movable support about the pivotal axis to differentworking positions relative to the movable support; whereby the workingforces applied by the support to the tool is transmitted through thehousing from one end of the body to the other end of the body withoutsubjecting the body between its ends to said forces; anD power means aremounted on the movable support and connected to the housing so as to beoperable to manipulate the housing and thereby the hammer, to differentpositions relative to the power driven movable support and against thework with working force.
 8. A pneumatic hammer including an elongatedrigid body adapted to support a tool at one end; a pair of rigidsupporting plates arranged alongside opposite sides of the body; meanssecuring each plate fixedly to the body at the opposite ends of thebody, respectively; a first connecting means on and rigid with theplates at the other end of the body and adapted for pivotally connectingthe plates to a movable power driven support for rocking as a unit, withthe body, about a predetermined axis extending transversely of the body,and operative to transmit directly to the plates at said other end ofthe body any heavy working load forces imposed by the movable support;second means on, and rigid with, the plates at said other end of thebody and offset transversely from said predetermined axis and adaptedfor pivotal connection to a reciprocable power device on said supportfor rocking the plates and body as a unit about an axis offset from saidpredetermined axis and operative to transmit heavy working load forcesfrom said reciprocable power device directly to the plates at said otherend of the body; and said plates, when secured to the body, in and ofthemselves, being sufficiently rigid and strong to transmit directlyfrom each end of the plates to the other end of the plates, bothlongitudinal and transverse heavy working load forces applied to theplates at said other end through the first and second connecting means,and to said one end of the plates through said tool end of the body.